Electrovesicograms (EVG) were studied in 20 women with stress urinary incontinence (SUI) and 12 healthy female volunteers with a mean age of 44.8 and 48.2 years, respectively. Recordings were performed by means of three electrodes applied to the skin in the hypogastric area and one reference electrode to the lower limb. In the 12 healthy women pacesetter potentials (PPs) were recorded as regular triphasic waves. Of the 20 SUI patients 16 showed normal EVG, and the remaining 4 exhibited 'tachyvesica', i.e. increased PP frequency. These 4 patients proved to have combined urge and stress incontinence with detrusor hyperreflexia. It was concluded that SUI patients have normal EVG unless there is an associated pathology.